Poka: A Necro‐Robot Beetle with a Measured Payload Ratio of 6847%

Abstract

This paper is concerned with the design, manufacture and validation of ‘Poka', a novel millimetre‐scale necro‐robot aimed at bridging the performance gap between miniature robots and insects. To create Poka, the exoskeleton of a deceased five‐horned rhinoceros beetle ( Eupatorus gracilicornis ) is used as a mechanical chassis, which is mechatronically functionalised to enable ambulation. When comparing the payload ratio, PR, of Poka against reported values of the rhinoceros beetle Xyloryctes thestalus , it is found that Poka's PR is more than two‐fold higher, reaching a measured maximum of 6847% (i.e., 68.47 times its own body weight). The specific power at maximum payload, P s,t , is nevertheless of the same order of magnitude in both Xyloryctes thestalus (0.21 W/kg) and Poka (0.28 W/kg). Poka's highest average speed, (1.55 mm/s), is achieved at a PR = 2739%, after which it progressively decreases with increasing PR, reaching its minimum = 1.3 mm/s at maximum PR. When comparing Poka's maximum measured PR of 6847% against those of 17 other ambulating robots, it is found that Poka's PR far exceeds that of any other robot to date, the highest being otherwise from SuperBot, who has a PR = 530%. Poka's PR is therefore the highest robot PR recorded to date and this is attributed to (a) the use of the beetle body as a natural composite chassis with high specific properties and (b) the additive manufacture of bionic beetle parts using low density but stiff polylactic acid, designed with structurally stable geometries.